Recent Changes in the Near-Infrared Structure of η Carinae

Abstract

Near-infrared imaging at two phases in the 5 yr spectroscopic cycle of η Carinae reveals changes in the spatial structure of the inner core that may be related to recently reported near-infrared photometric variability. The central source changed from a pointlike object to a more extended, bipolar or shell structure. This behavior is reminiscent of changes observed in the radio continuum. NICMOS images show a toroidal distribution of dust and gas around the central star and confirm the morphology of several other structures observed in ground-based images of the Homunculus. The morphological variations appear to be confined to the central core of the nebula.

Based on observations made with the NASA/ESA Hubble Space Telescope, obtained at the Space Telescope Science Institute, which is operated by the Association of Universities for Research in Astronomy, Inc., under NASA contract NAS5-26555.